Summary: to be published in Modeling the Performance of Engineering Structural Materials III" (Don
Lesuer, T.S. Srivatsan and Eric Taleff eds.), Proc. TMS Fall Meeting, Columbus, OH 2002.
COMPUTER MODELING OF DISLOCATION
MOTION IN FINE-SCALE MULTILAYERED COMPOSITES
Peter M. Anderson, Qizhen Li
Materials Science and Engineering
The Ohio State University
2041 College Rd.
Columbus, Ohio 43210
Abstract
A classic method of strengthening materials to plastic deformation is to refine the
microstructure, so that barriers to dislocation motion occur more frequently. An extreme
example of this approach is to decrease the individual layer thickness in multilayered
composites to several nanometers. We simulate dislocation motion in such materials with a
cellular automaton method, in which slip planes are discretized into equilateral triangular
patches that slip according to an energetic driving force. In our model, there are regimes within
which lattice mismatch, the residual stress state and misfit dislocation structure are primary
sources of confinement. The results show that decreasing the layer thickness can increase
composite strength, so that dislocations are confined to smaller volumes of material. The
simulations help one to visualize the confinement process and define the role of lattice